Questions tagged [ieee-802.1w]
For questions about Rapid Spanning-tree protocol (RSTP). For instance, you are troubleshooting an issue where Spanning-tree is not forwarding the correct VLANs on your trunk.
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RSTP convergence of p2p links
Ramping up on RSTP here. One thing that is unclear to me is how RSTP links converge initially on P2P links. Consider the classic 3 switch topo as below:
For RSTP, won't all the links move to ...
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1
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139
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Equivelant of ciscos "spanning-tree portfast disable" in Juniper parlance
On our cisco network switches we have the following configuration:
interface GigabitEthernet1/0/1
description Main Internet 1
xxx
spanning-tree portfast disable
spanning-tree bpduguard disable
I ...
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How would a switch know that it should forward a frame through a different interface in a STP topology?
Imagine the following STP topology
If PC0 was to ping PC1, all of the switches would create entries in their MAC table according to the source MAC address of the PCs associated with the corresponding ...
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Does RSTP also maintain correct mac table entries?
I've got 4 switches connected in a circle and they all run RSTP. Lets assume the following:
switch A (root bridge) ------- switch D
| |
| ...
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2
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1
answer
930
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RSTP / MSTP use cases and best practices
Hi, what would be the best practice to achieve separate tree topologies for each of the rings? Two options come to my mind, although I do not completely understand IF RSTP can be made VLAN-aware ...
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STP convergence process needs detailed explanation, please
So, I understand how STP convergence works on high-level. However, when I am trying to look into the process deeper, I run across some doubts I would appreciate someone could clarify to me.
Here we go:...
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1
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332
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Why does only the root bridge send RSTP BPDUs after sync?
From a recent packet capture, after the sync process in RSTP, only the root bridge sends RSTP BPDUs every 'hello' interval. Why is it so?
Shouldn't all switches send BPDUs every 'hello' interval since ...
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Why does RSTP send proposal bit and agreement bit as '1' initially?
From a recent Wireshark capture of a RSTP BPDU on a switch, both proposal and agreement bits were set to '1'.
In my understanding, initially both switches 'propose' themselves as root. The better root ...
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2
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254
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RSTP Separation
Topology:
(Ring Network A)----[Router A]-------(Possibly Ring Network C)-------[Router B]----(Ring Network B)
Goals
I need Router A to always be the RSTP root bridge for Network A.
I need Router B to ...
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2
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594
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RSTP: Max Aging and Device Count
I have a question about the RSTP ethernet swtiches, I have 40 RSTP ethernet switches, they connect with the line topology and root birdge is 23th device on the line.
I am using just 23 device for this ...
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RSTP Network Switches Port Base MAC Address
How to ethernet managable network switch manage the dynamic table entries although receive "port base MAC address frame" like RSTP,STP protocole ?
I know the dynamic mac table save the ...
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1
answer
277
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BPDU Guard With RSTP Devices
I am attempting to secure our switches with BPDU Guard. I have it enabled and I have a pieces of equipment with 2 NIC ports on them of which they can be daisy chained together for data collection. ...
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1
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RSTP Network Switch MAC address
I'm confused about something I'm new to this, for example I use network switches in my network they support RSTP protocole, So let say every switch have 5 port. Switch base MAC address , aa:bb:xx:yy:...
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In RSTP, where all switches generate their own BPDUs, are they limited to forwarding them only on designated ports? (like in classic STP)
I recently learnt a rule in STP: only Designated ports forward BPDUs.
However, I'm not sure about this in RSTP since ALL switches generate their own BPDUs every few seconds. So, in a certain LAN ...
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1
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419
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RSTP sending BPDUs out of the network switch?
I need some information about RSTP
If the port state is blocking, discarding alternate .
Should BPDU be sent to external ports? I cant see any BPDU in wireshark if the port states Alternate,Discarding ...
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STP configurations
In my design, there will be a few be a few rings of edge switches that are connected to my distribution switch. (alcatel 6860-U28) The distribution switch will then be connected to my core router ( ...
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2
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RSTP Loop - 24 switches, Max RSTP Diameter and timer adjustments?
First time poster and the more I read aboud RSTP, the more questions I have in relation to my situation.
I have found myself recently assigned to a project that has been essentially delivered on a ...
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2
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1k
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Do I need STP enabled on all switches in a loop?
I have a network architecture where each of my N switches is connected to two others, making it a perfect loop. For example see the diagram below:
I know that in order to avoid broadcast storms, I ...
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RSTP Sync received every 2 minutes after a TC
While digging into logs (debug spanning-tree event has been enabled) in order to troubleshoot communication losses after topology changes.
I was able to notice once I triggered a TC, one specific ...
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Fastest way to switch between redundant wireless links
I have a system using 2 redundant point-to-point wireless links to access the internet, and I'm trying to find the fastest way to switch between them if one goes down.
We need to switch within 1 ...
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What is the impact of VTP pruning against RSTP topology?
While working on a network using VTP (without pruning yet), I noticed the STP topology (for VLAN 10 let say as an example) was including all switches even the ones not having any interface in the VLAN ...
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99
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Endianness of data fields inside BPDU
I'm working on a frame/packet decoder and am seeing inconsistent data regarding the endianness of the MaxAge/Hello/ForwardDelay fields inside a spanning-tree BPDU.
Below is a picture of a wireshark ...
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STP Priority field and 4 bits in multiples of 4096
For the STP Priority Field, how do you get "multiples of 4096" out of 4 bits?
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460
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Brocade/Ruckus per vlan spanning tree vs Cisco
Brocade = (config-vlan-10)#spanning-tree rstp
This seems to enable rstp per vlan. This example enabling it on vlan 10.
Cisco = spanning-tree mode rapid-pvst
This enables Rapid PVST+ under the covers ...
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2
answers
1k
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RSTP recovery time with Ethernet ring
I am trying to test Rapid Spanning Tree on an Ethernet ring. Most of what I found does not seem to apply to my specific situation, but I am happy to be pointed elsewhere.
Specifically, I have one ...
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2
answers
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Fastest spanning tree in multiple-ring topology
I have a topology in which there is a main ring and some nodes in the main ring have a minor ring.
1- which STP configuration has the fastest convergence time? How would you configure spanning tree ...
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282
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Spanning Tree Priority Vectors
Out of personal interest I am working my way through the IEEE standards 802.1D-2004 and 802.1Q-2014. I am using the earlier document to clarify meaning in the later document, since the addition of ...
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2
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spanning tree loop with bpdufilter on acces port but not on trunk?
┌─────┐ ┌─────┐
| A ┼------┼ B |
└─────┘ └┬───┬┘
└---┘ <-- loop
behold the above drawing. this is a test setup connectin switch A and B, and a test loop
A: cisco ...
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1
answer
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Edge detection on designated ports
If a switch doesn't receive a BPDU on a particular port it marks this port as "Edge Port". But any designated port won't receive any BPDU even though it was connected to other switches since their ...
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1
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Trying to configure STP on a small network and have a few questions
I am trying to configure the switches on a network to use STP or RSTP but I'm confused about how to do this. The network consists of 3 switches, all on the default subnet, so a fairly simple setup. ...
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1
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309
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What considerations should I need to have in order to configure a RSTP over a PTP wireless network?
I have configured a PTP wireless network that requires RSTP protocol in order to manage redundance loops. Most of the loops are 4 points big, but there is a big one of more than 15 points. The most of ...
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Adding new switch to Spanning Tree network
Currently studying Spanning Tree, I'm not sure about the behaviour when we add a new switch to an existing STP topology (with cisco pvst+).
Assuming we plug this new bridge called S4 with only one ...
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Does a switch generate TCN BPDU when it elects a new root bridge?
what are the scenarios in which a switch generates a TCN BPDU other than when a port goes down or come back up?
switch-1---------------switch-2----------------switch-3
(root bridge) (Non Root)...
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3
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BPDU exchange between RSTP switches
According to the documentation:
BPDU are sent every hello-time, and not simply relayed anymore. With 802.1D, a non-root bridge only generates BPDUs when it receives one on the root port. In fact, a ...
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4
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H3C MST BPDU exchange failing
I am coming across the following MST issue.
Between a HP5940 network core and HP5130 network access layer, I am using 5 instances of MST, configured like this :
CORE switch
stp region-configuration
...
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1
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590
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STP interface command shutdown STP globally
I'm in the process of studying to renew my CCNP again. 3 years comes and goes awful fast! While working on my lab gear I thought I wonder if I can shut down STP on a single interface like I've done in ...
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RSTP 802.1w maximum network loop diameter
Can anybody direct me to a calculation of the maximum network diameter (number of devices) on an RSTP tree (RSTP, NOT STP)?
As far as I can understand from the standard and the RFC, there is no such ...
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When exactly the Proposal and Agreement flags are used in RSTP
When does the flags proposal and agreement are set in RSTP? What are its importance?
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Why is there a large difference between BPDUs sent and received counters for RSTP root port?
I just noticed a big difference in numbers looking at the sent and receive counters for RSTP BPDUs.The port I'm looking at is a root port. I see a very less number of BPDUs sent against to BPDUs ...
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RSTP Troubleshooting
We have about 30 switches (multiple vendors) in a network which consists of a main ring and several branches. A couple of the branches may have loops. Some of the switches are smart switches with ...
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How do I physically measure the re-convergence delay while RSTP determines the new topology after link loss?
I have a simple network with two switches redundantly connected to each other and several computers on each switch talking back and forth across the two switches. The switches support RSTP/MSTP.
I ...
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How fast can STP, RSTP, and MSTP find a new route?
If I have two switches connected redundantly and both are capable of using STP, RSTP, or MSTP, how quickly can an alternate route be detected and normal communication resume if the main route is ...
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1
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RSTP Vs STP Vs MSTP
I am sure this is a common question but would like to know the best practices. I have a pair of Juniper routers connecting to a IRFed HP 10k core switch. My HP core runs stp and we are tyring to ...
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3
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Bridge is always root for a vlan
I have a switch that is not receiving BPDU Hellos properly and I have not been able to pin point the problem. Switch 1 puts all ports for vlan4 into desg mode and claims it is the root for vlan4 (the ...
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how ping a PC by another switch's console use secureCRT in rstp [closed]
In secureCRT SWC's console ping PCA in rstp demo in the pic?
It's a loop Topology and on each switch I set stp mode rstp and every ports are bind default vlan1.
I open the switchC's loopback 0 and ...
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Cisco 2960: RSTP finished when?
I have several Cisco 2960 switches here, all configured for RSTP.
15.0(2)SE6
C2960-LANBASEK9-M
spanning-tree mode rapid-pvst
Topology is as follows:
S1 -- S2 -- S4
\ /
\__S3__/
I ...
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